Consolidated Statements of Stockholders' Equity - USD ($) shares in Millions	Total	Common Stock Issued [Member]	Additional Paid-in Capital [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Treasury Stock at Cost [Member]
Beginning balance at Dec. 31, 2018	$ (149,600,000)	$ 900,000	$ 1,078,800,000	$ 1,855,000,000	$ (188,800,000)	$ (2,895,500,000)
Beginning balance, Treasury shares at Dec. 31, 2018						47.3
Stockholders' Equity [Roll Forward]
Cumulative Effect Period Of Adoption	(300,000)			(300,000)
Net income	408,700,000			408,700,000
Dividends	(114,700,000)			(114,700,000)
Foreign currency translation adjustments, net	5,800,000				5,800,000
Pension and postretirement liability changes, net of tax expense (benefit)	73,000,000.0				73,000,000.0
Stock-based compensation expense	21,300,000		21,300,000
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), after Reclassification, before Tax	6,200,000				6,200,000
Treasury shares reissued for common stock, shares						(0.3)
Treasury shares reissued for common stock	3,400,000		6,600,000			$ 10,000,000.0
Treasury stock purchases, shares						(1.6)
Treasury stock purchases	(424,000,000.0)					$ (424,000,000.0)
Ending balance at Dec. 31, 2019	(170,200,000)	900,000	1,093,500,000	2,148,700,000	(103,800,000)	$ (3,309,500,000)
Ending balance, Treasury shares at Dec. 31, 2019						48.6
Stockholders' Equity [Roll Forward]
Cumulative Effect Period Of Adoption	(1,300,000)			(1,300,000)
Net income	356,300,000			356,300,000
Dividends	(117,900,000)			(117,900,000)
Foreign currency translation adjustments, net	800,000				800,000
Pension and postretirement liability changes, net of tax expense (benefit)	(1,200,000)				(1,200,000)
Share of equity method investments other comprehensive income	(1,200,000)
Stock-based compensation expense	24,300,000		24,300,000
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), after Reclassification, before Tax	8,200,000				8,200,000
Treasury shares reissued for common stock, shares						(0.3)
Treasury shares reissued for common stock	3,000,000.0		4,600,000			$ 7,600,000
Treasury stock purchases, shares						0.5
Treasury stock purchases	(117,900,000)					$ (117,900,000)
Ending balance at Dec. 31, 2020	(17,100,000)	900,000	1,113,200,000	2,385,800,000	(97,200,000)	$ (3,419,800,000)
Ending balance, Treasury shares at Dec. 31, 2020						48.8
Stockholders' Equity [Roll Forward]
Net income	464,000,000.0			464,000,000.0
Dividends	(130,500,000)			(130,500,000)
Foreign currency translation adjustments, net	(7,300,000)				(7,300,000)
Pension and postretirement liability changes, net of tax expense (benefit)	13,900,000				13,900,000
Stock-based compensation expense	24,300,000		24,300,000
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), after Reclassification, Tax	400,000
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), after Reclassification, before Tax	2,500,000				2,500,000
Treasury shares reissued for common stock, shares						(0.2)
Treasury shares reissued for common stock	3,300,000		3,800,000			$ 7,100,000
Treasury stock purchases, shares						1.9
Treasury stock purchases	(622,100,000)					$ (622,100,000)
Ending balance at Dec. 31, 2021	$ (269,000,000.0)	$ 900,000	$ 1,133,700,000	$ 2,719,300,000	$ (88,100,000)	$ (4,034,800,000)
Ending balance, Treasury shares at Dec. 31, 2021						50.5